Clean up OpenSSL usage a bit
This is a pair of changes to clean up OpenSSL usage a bit.
The first removes a call to BN_GENCB_old in favor of just passing in a NULL BN_GENCB, which is simpler and more supported by documentation. (The docs don't say the callback can be NULL. It just happens that OpenSSL allows it for the "old" mode but not the "new" one.)
The second removes some stale DH_clear_flags calls. The commit description has a record of what they seem to be from and why they are, I believe, no longer necessary. They're a workaround for a bug that was fixed in OpenSSL 0.9.7h.
Closes #3406 (closed)
Edited by Michał Kępień